Disulfide bonds are covalent bonds formed post-translationally by the oxidation of a pair of cysteines. A disulfide bond can serve structural, catalytic, and signaling roles. However, there is an inherent problem to the process of disulfide bond formation: mis-pairing of cysteines can cause misfolding, aggregation and ultimately result in low yields during protein production. Recent development...

The relationship between protein synthesis, folding, and disulfide formation within the endoplasmic reticulum (ER) is poorly understood. Previous studies have suggested that pre-existing disulfide links are absolutely required to allow protein folding and, conversely, that protein folding occurs prior to disulfide formation. To address the question of what happens first within the ER, that is, ...

The formation of native disulfide bonds is an essential event in the folding and maturation of proteins entering the secretory pathway. For native disulfides to form efficiently an oxidative pathway is required for disulfide bond formation and a reductive pathway is required to ensure isomerization of non-native disulfide bonds. The oxidative pathway involves the oxidation of substrate proteins...

Disulfide forms of homocysteine account for >98% of total homocysteine in plasma from healthy individuals. We recently reported that homocysteine reacts with albumin-Cys(34)-S-S-cysteine to form homocysteine-cysteine mixed disulfide and albumin-Cys(34) thiolate anion. The latter then reacts with homocystine or homocysteine-cysteine mixed disulfide to form albumin-bound homocysteine (Sengupta, S...

Configuration transitions of individual molecules and atoms on surfaces are traditionally described using an Arrhenius equation with energy barrier and pre-exponential factor (attempt rate) parameters. Characteristic parameters can vary even for identical systems, and pre-exponential factors sometimes differ by orders of magnitude. Using low-temperature scanning tunnelling microscopy (STM) to m...

A general strategy to tune the achiral main chain polymers into helical nanoassemblies was proposed based on the co-gelation approach. As an example, two achiral main chain polymers, PCz8 and PSi8, were selected, and their co-assembly with an amphiphilic l- or d-glutamide gelator was investigated. Although the polymers could not form gels individually, they could form co-gels with the gelator a...

A new direct method for the measurement of red cell lithium was compared with the indirect method. Good correlation (r = 0.97) was found and the coefficients of variation of the direct and indirect methods were 3.9% and 5.5%, respectively. In the direct method red cells suspended in choline chloride were centrifuged through dibutyl phthalate, which removes plasma adherent to the cells. A haemol...